Most of us know that exercise is good for us. It boosts circulation and tones the cardiovascular system. It builds strength, burns calories and reduces depression. It improves insulin sensitivity in people with diabetes. It may even help delay the onset of Alzheimer's disease. But can you even imagine that it can partially reverse aging at the cellular level.

In a study appearing this week in the online journal PLoS geneticists looked at the effects of six months of strength training in 25 elderly volunteers aged 65 and older (average age: 70).

"To be honest, we were expecting some indication that the exercise program improved strength," says biologist Simon Melov, director of genomics at the Buck Institute in Novato, Calif., and coauthor of the study. What the scientists didn't expect was what they actually found—that after six months of resistance training, there were dramatic changes at the genetic level. As Melov puts it, "The genetic fingerprint [of the elderly participants] was reversed to that of younger people—not entirely, but enough to say that their genetic profile was more like that of young people than old people."

What kind of workout routine does it take to produce these changes? The seniors went through a rigorous exercise program—an hourlong session of strength training twice a week for six months, using the same types of machines found in most gyms. At each session, they performed three sets of 10 contractions for each muscle group, similar to a standard workout (albeit using lighter weights than most young people would use). Trainers and kinesiologists were on hand throughout to make sure the participants used the machines properly and did not injure themselves.

The take-home message is clear. "It's never too late to start exercising," says Tarnopolsky. You're only as old as your genes.
Source: MSNBC